The proposed event, revealed by the LA Times, is to take place in California in October and is being described as a "mega festival".

Organised by the people behind Coachella, America's version of Glastonbury, it is also drawing comparison to Woodstock, that near mythic gathering of the Sixties that effectively established the very idea of the rock festival as a cultural event somehow bigger than mere entertainment, a coming together of the greatest talents of the day with the biggest audiences ever seen in a celebration of music and brotherly love.

But there is one very big difference.

While Woodstock celebrated the first incredible creative flourish of rock culture, this line-up effectively commemorates the end of the rock era.

When The Who played Woodstock in 1969, guitarist Pete Townshend was 23 years old and singer Roger Daltrey 25. Now they are both in their 70s - as is every other artist on this bill - and the rest of their band are dead. These are not the vanguard of popular culture but road-tested veterans, still touring with sets almost completely reliant on hits of yesteryear.

Of course, the excitement generated by news of this concert is understandable. These are some of the most important rock stars of the last 50 years, who have consolidated their reputations with some of the greatest recordings and performances ever witnessed.

And they have never all appeared on the same bill together. Who wouldn't want to see something like that?

The Rolling Stones as they look today

For older fans, it will seem like a coming together of the gods. For younger fans (that is, anyone under 70) it will be a chance to witness the originators of modern pop culture before they shuffle off the stage (something none of them seem to be in a hurry to do).

But the big question about a line-up like this is: what does it say about the state of contemporary music and culture?

As well as the copious drugs and nudity there was also a fierce idealism amongst the 400,000-strong crowd.

The festival, contrary to the illusion of order created by the famous 1970 documentary, was also a total, muddy shambles. Many of the acts were much the worse for wear after binging on drugs and alcohol. Main headliner Jimi Hendrix didn't go on stage until nine in the morning because the concert was running so late.

This year's mega festival, you can be certain, will feature no such amateurism - and is very unlikely to be free. The average age of attendees, it is fair to assume, will be considerably higher than it was at Woodstock.

It won't have the same creative or cultural legacy, either.

McCartney, the Stones and Dylan, of course, contributed to the culture that gave birth to Woodstock (even though none of them actually performed at it). They stand as iconic representatives of a utopian rock vision. But they can no longer be described as pioneers.

If we try and imagine a comparable festival line up in 1969, it would be headlined by Bing Crosby, Ella Fitzgerald, Louis Armstrong, Benny Goodman and maybe feature an appearance by the Glenn Miller Band, without their deceased leader, obviously.

And who might be called on to perform at an event comparable to Woodstock today? The biggest stars of living, breathing youth culture are Adele, Taylor Swift, Ed Sheeran, Justin Bieber, Beyoncé and Lady Gaga. Not a lot of rock on offer there. And not a lot that would add up to anything more idealistic than a big party in a field, a backdrop for an audience live-tweeting selfies.

Of course, it should be noted that Woodstock did not actually feature many of the biggest stars of the day.

The only stars thus far announced for California who were at Woodstock are The Who and Neil Young. The Doors cancelled because they thought it would be a second-rate repeat of 1968's Monterey Festival. Led Zeppelin, the Moody Blues, Free, Frank Zappa, Joni Mitchell and the Byrds all declined invitations.

But the event became bigger than its headliners, making stars of Santana, Joe Cocker, Creedence Clearwater Revival and other artists low on the bill.

Perhaps one of the reasons veteran live acts continue to thrive is because this kind of music lends itself particularly well to mass singalongs. It may be old fashioned and out of date but rock contains within it a kind of drama that today's pop cannot match, with physical punch, visceral power and meaningful songs that have become anthems across generations.

The incredible line up of 70-something legends makes you wonder what we are going to do when they are no longer around?

Sure, there's another generation of classic rockers who followed in their wake, and maybe next year it will be the turn of U2, Bruce Springsteen, Metallica, Guns N' Roses, Radiohead and Coldplay, but even that line-up sounds diminished by comparison.